Screen Printing Explained

No matter how much you love or hate shopping, you've gotta have clothing. Custom printing enhances a basic garment and turns it into something attractive, eye-catching, and even hilarious. If you've ever stopped to ponder how all those images and sayings get on printed t-shirts, this rundown will get you up to speed. The most common way to decorate a t-shirt is screen printing, a complex process that leads to a beautiful result. Step one is the design. Generally, we need a vector file with the art, because that type of file can be resized and still look crisp and clear. Most of the time, screen printing designs are "spot color," which means they're made up of a few solid colors, rather than a full-color photo-like image. We identify the colors with PMS (Pantone Matching System) numbers, so we get the ink mixed up just right. Step two is creating the screens. Similar to a large stencil, a screen lets us apply ink to the shirt right where we want it and nowhere we don't. We need one screen for each color. If we wanted to print "Hello, world!" on a t-shirt, with "Hello" in red and "world" in blue, we'd need one screen that just said "Hello" and one screen that just said "world." Step three is the choosing the ink. There are many choices for screen printing ink. Plastisol ink is used most often. It's made of PVC particles suspended in an emulsion and it won't harden if left open, which makes it easy to work with. T-shirts screenprinted with plastisol ink don't dry, per se; they go under a heat lamp to cure the ink and make the imprint last. Plastisol is the least costly screen printing ink, but large designs can feel rubbery due to its synthetic nature. When a softer feel is desired, water-based ink can be used. Discharge inks are even better when touch is important, since they actually dye the fabric and cannot be felt at all. A variety of specialty inks including neon and glow-in-the-dark are also available for unique projects. Step four is applying the ink to the shirt - in other words, the actual printing. Printing happens one color at a time. The first screen is lowered onto the shirt and the appropriate color of ink is pulled across the screen with a squeegee. Then the second screen, the third, and so on, for however many colors are in the design. Color by color, the full design comes into view. It's possible to do all this on a simple tabletop press, but most of our jobs are printed on automated hydraulic presses that speed the process up. This is why screen printing jobs are priced according to the number of colors. Each additional color is an additional step and some extra labor. Screen printing isn't the only way to decorate a t-shirt, of course. One alternative is called dye sublimation, or dye sub for short. This method involves transferring the image from heat-resistant paper onto the shirts, where extreme heat turns the ink into a gas that binds to the fabric at the molecular level. It is slow and labor-intensive, but it allows for vibrant full-color images that cover the garment completely. Dye sub printing can only be done on polyester fabric. Because we're familiar with a wide range of printing options, Gorilla Marketing can advise you what might be best suited to your project and budget. Want to learn more? Contact us and we can get you rolling on the screen printed t-shirts of your dreams!